University of Texas Bulletin
No. 1711: February 20, 1917
Pure Milk and How to Get It
THE DEPARTMENT OF EXTENSION OF
THE UNIVERSITY OP TEXAS
BABY HEALTH IS TEXAS' WEALTH
Published by the University six times a month and entered as second-class
matter at the postofflce at Austin, Texas
The benefits of education and of
useful knowledge, generally diffused
through a community, are essential
to the preservation of a free govern-
Cultivated mind is the guardian
genius of democracy. . . . It is
the only dictator that freemen ac-
knowledge and the only security that
President Mirabeau B. Lamar.
Pure Milk and How to Get It
There is a world of wisdom in the saying, "Mother's milk
for babies, and cow's milk for calves," but, unfortunately, it
is necessary at times to feed infants on food other than mother's
milk, and modified cow's milk is the best substitute. Moreover,
all babies after a year of age, need for some time good, clean
cow's milk for a large portion of their dietary. Hence it is
necessary to study the problem of a pure milk supply for our
Some of the reasons why we should study the milk problem
1. M!ilk is an opaque liquid, and hence conceals, to a marked
degree, any impurity.
2. It is a splendid food for bacterial life.
3. A great deal of it is used in the raw state.
Let us examine these points more closely. We find that if
we try to look through a quantity of milk to discover its con-
dition, we cannot see what it contains. If it were clear like
water, we would very frequently fiind a sufficient bacterial
growth to produce a cloud visible to the unaided eye. The most
common dirt in milk is cow manure. This may be in good-sized
pieces, but more often it is in very finely divided particles aiid
also in solution. One error in fairly common use is the strainiiig
of milk, as it comes from the cow, by means of a cheesecloth
over the top of the pail. This holds the particles as they ''all,
and the streams of milk falling on them with considevable lorce
tend to break up the masses and carry the smaller particles
through the cloth. Aside from these, the streams wash the
larger insoluble masses, carrying the bacteria through. Milk
obtained in this way always has a much higher bacteria con-
tent than that not so handled. When you look at the bottom
of a bottle of milk and see a sediment, remember that not only
the greater part of this sediment is cow manure, but a far
greater amount has gone into solution and is not visible.
After the bacteria get into the milk, they are in a medium
that furnishes all the food thev need or desire. Milk is one
4 University of Texas Bulletin
of the best of our culture media, and in the laboratory is used
very frequently for growing bacteria. The rate of multipli-
cation under favorable conditions is extremely rapid, the aver-
age time required being between twenty and thirty minutes.
Since each bacterium divides into two, and these continue to
increase at the same rate, it can be readily seen that milk must
be kept as free from bacteria as possible, especially when it is
to be used as an article of diet for an infant.
The essentials for a pure milk are cleanliness, freshness, and
low temperature. No milk can be pure unless it is i)roduced
in a cleanly manner, and the number of bacteria in milk is an
index of the manner of production and handling.
The milk may be contaminated from disease of the cow, or
from manure, dust, dirty containers, or dirty hands. It may
also become contaminated by the act of coughing or sneezing
over or near and in the direction of the container. Contami-
nation from the human source is the most dangerous, as it is
from this source that most of the disease-producing organisms
come. No one should milk or handle the milk who has a sore
throat or any sores on the hands. Above all, cleanliness in
both the containers and in the dress and hands of the milkers
should be secured.
Milk should be cooled as soon as possible afte'r milking, and
it should be kept at a temperature of not over 50 degrees Fah-
renheit until used. The souring of milk is caused by the action
of bacteria of a particular kind — the lactic acid bacteria. These
act on the sugar in the milk, changing it to acid and water.
When milk sours quickly, it is a sure sign either that it has
not been kept cold or that it is not clean.
The examination of milk is of two kinds — chemical and bac-
teriological. These are for two distinct purposes. The chem-
ical examination is made from an economic or administrative
standpoint. Such an examination reveals the adulteration of
milk, but it has, except when preservatives or gross adulteration
are found, but little health signifieance.
The bacteriological examination, on the other hand, is largely
for purposes of prevention of disease. This examination shows
where inspection of the dairies is needed, and in this way save .
Pure Milk and Hoiv to Get It 5
labor and much time for the inspector. The findings of the
bacteriologist indicate if there is a failure on the part of the
dairyman to keep his product in sanitary condition but they
go no farther. The inspector, by following up the counts, can
locate the cause of the high bacterial content. The milk in-
spector should co-operate with the dairyman in every way, and
aid in locating any failure to produce clean milk.
The greater the co-operation between the producer, health
department and consumer, the greater the chance of a clean
The consumer has a vital interest in the character of the
milk served to his community. How many consmners know
from personal observation the conditions under which this im-
portant article of their food is produced? How many know
if the cows producing the milk have passed the tuberculin test?
How many know if the cows and the sheds are kept clean and
free from flies? How many know if the milk utensils are
cleaned and sterilized? How many have stopped to think that
it costs more to produce a clean milk than a dirty one, and that
as long as all milk commands the same price, there is no induce-
ment to clean up? Can we expect a producer to expend the
necessary money and care to give a clean supply when his
neighbor with no expense and no care can get the same price
for an inferior article? These are points to be considered, and
the remedy is in the hands of the consumer.
After milk reaches the consumer, it should be properly cared
for. Before opening a bottle of milk the outside of both the
bottle and cap should be washed and wiped with a clean cloth
or towel. After the cap has been removed, do not replace it,
but cover the bottle with a clean, inverted glass or cup. This
will be a convenient and clean cover.
Keep the milk on ice; do not return to the bottle any milk
that has been poured out, but keep this in another receptacle.
Milk readily takes up odors and flavors, consequently articles
that can impart either odor or flavor — such as fish, onions, tur-
nips, cantaloupes, etc., should not be kept near the milk.
Milk should not be allowed to stand exposed to warm weather
between delivery and the time it is put on ice. Remember that
6 University of Texas Bulletin
the milkman is responsible until he has delivered his product.
The responsibility then rests oi) the consumer.
The cleanest possible milk should be used for infant feeding-,
and this should be pasteurized in the home. Pasteurization is
not a substitute for cleanliness but an added safeguard. By
pasteurization is meant the heating of milk to 140 degrees F.,
and holding it there for twenty minutes; but it is safer to add
5 to each process — i. e., 145 degrees and twenty-five minutes.
The milk should then be cooled as rapidly as possible, and kept
on ice until ready for use. In preparing the milk for the use
of the baby, do not test the temperature by putting the mouth
of the bottle or the nipple to the lips. A few drops on the
wrist is a good indicator of the temperature.
A word in regard to commercially pasteurized milk may not
be amiss. Much of the milk sold under this label has no right
to be called pasteurized milk. No milk should be allowed to
bear the label "Pasteurized Milk" if it has a count of over
50,000 bacteria per c. c. — about fifteen drops — after pasteuriza-
tion, for either it has not been properly pasteurized or it has
been kept too long after pasteurization before it is sold for use.
As the disease-producing bacteria are derived almost entirely
from human sources pasteurization is a means by which this
danger can be reduced to a minimum, but it should never be
used to cover up dirty methods of handling.
The qu&stion of a pure milk supply is a great one, and will
never be solved until all the parties — producers, health depart-
ments, and consumers — understand each other and work together
for the desired end, that end being a product pure and safe
for human consumption.
A FEW RULES FOR PRODUCING PURE MILK
1. Cow must be healthy as shown by the tuberculin test
and a physical examination by a veterinarian.
2. Cow must be clean-flanked and udder washed and wiped
with a clean cloth.
3. No feeding should be done at or just previous to time
of milkinf=r, as this causes dust.
4. Milker should wear clean, clothes and have clean, dry
5. Mlilking-stool must be clean as it is the last thing the
milker touchas before milking.
6. All milk utensils must be absolutely clean.
7. As soon as the milk is drawn from the cow it should
be removed to the milk room and should be cooled as rapidly
8. It should then be kept at or below 50 degrees Fahren-
heit until ready for use.
IN THE HOME
1. Milk should be put in the ice chest as soon as delivered.
2. There should be a compartment for the milk, as odor and
flavors are quickly taken up by milk.
3. Always wash of£ the bottle and cap before opening, and
do not return the cap, but invert a clean glass or cup over
the bottle if there is a portion left.
4. Never return to the bottle any milk that has been poured
out, as the milk will not keep as long. Keep this milk in an-
5. Do not allow the bottle to be kept outside the ice chest
while cooking. If milk is wanted pour out the needed amount
and put the bottle back on ice.
6. Know where your milk comes from and how it is handled,
and after you receive it give it proper care.
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limm^ OF CONGRESS